NAT configuration?

i am running Asterisk behind NAT, my SQUID is 58.65.151.218 while the Asterisk server is running at 192.168.0.30, i have given following commands at squid

[code] iptables -t nat -A PREROUTING -i eth0 -d 58.65.151.218 -p udp --dport 10000:20000 -j DNAT --to-destination 192.168.0.30

iptables -t nat -A PREROUTING -i eth0 -d 58.65.151.218 -p udp --dport 5060 -j DNAT --to-destination 192.168.0.30[/code]

Same configuration is done at remote branch office SQUID.

and i have added following line in sip.conf

externip=58.65.151.218

but when we try to call each other using xten SIP phone we get NO ROUTE TO HOST error?

please help me out,

thanks